


Semper Vigilantem

by Ventisette



Category: Gravity Falls
Genre: Gen, Transcendence AU
Language: English
Status: In-Progress
Published: 2014-10-10
Updated: 2015-05-12
Packaged: 2018-02-20 17:13:30
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 4,169
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2436515
Author URL: https://archiveofourown.org/users/Ventisette/pseuds/Ventisette
Summary: <blockquote class="userstuff">
              <p>This is a fic for the transcendence Au [http://transcendence-au.tumblr.com/] revolving around Dipper inheriting all of Bills powers and all the head-canons that follow. [events in this one take place after/durring one of Mabel's reincarnations.] _( :3_|   ) I've fallen hard for it. </p><p>Come join us.</p>
            </blockquote>





	1. Broken

**Author's Note:**

> End notes contain spoilers. Don't read 'em till the end, please.

“Auuuugh...” Mabel kicked her legs in frustration from the sofa. Confined to suffer the boredom of afternoon tv by a full arm cast. (and by full, it was the whole arm. Wrist to shoulder on the right side.) Being unable to work on her piles of art projects, this could be considered a personal hell for her..

“It itches~! Bro-bro, Can you get me that straw?” She pointed to to a drink across the room. Well, across the room from her, it was right next to me. _My_ drink, _My_ straw...

She didn’t ask for the drink, though. Mabel wasn’t thirsty at all. She was gunna use the straw to get that itch. Figures…

“Mabes, Don’t you want the full drink, and not just the straw?” I was onto her little plan, and she probably knew that I knew. “I don’t see a drink near you in need of a straw.” I looked back at her with a grin.

“Sure I do. I do, in fact, have a drink. And it’s a very full glass...it’s….” She looked around her settings, trying to figure out how to trick me. “It’s there.” She pointed with her free hand to the glass next to me. “I don’t know how it got all the way over there~” Mabel grinned with a tone to her voice that clearly showed that she knew that there was no truth to her statement,. “Did you take it from me~?”

“Ahahaha, Gunna have to try harder than that if you wanna trick me. Luckily I have proof that this isn’t yours.” I grabbed my drink smugly and walked over to her so she could see the contents. “As you can see, this is...” I gave a nice smirk as the look on her face went sour.

“Pineapple juice...” Mabel’s eye narrowed. “We meet again, enemy of all the juices.”

There was silence. She glared at the glass before a smile started to interrupt her dramatic pause.

We both burst out laughing as she took the straw out in a single fluid motion.

“You sure you should be sticking a wet straw into the cast?”

“What could it hurt?”

Alot actually…I let out a sigh as I saw her get the itch.

“Aaaah, this hits the spot~”

__

Let’s rewind a bit. It all began when our parents decided we could use some fresh air. So, they sent us off to play in the woods equipped with a full array of monster bashing gear. Mabel, well she was good enough handling the monstery stuff. She pretty much armed herself with several different baseball bats, each different to meet different needs.

Myself on the other hand. I’m not so good with the fighting types. I’m kinda bad in the reflex section, as well as my depth perception is complete junk. No, I’m best when it comes to dealing with the intelligent monsters. The ones you can reason with.

This time, during our wonderful venture, I would have welcomed a rampaging manotaur to cross our path over who we ran into.

Gideon Northwest. That jerk had always had something against me since we had meet at the ripe era of pre-school. Our families got along rather well, but for some reason, Gideon was always sour towards me in particular.

“Pines. We meet again.” He scowled at me, then turning to my twin, “And Hello Mabel~Lovely afternoon isn’t it.” He reached out to kiss her hand while she made a grossed out face and noise.

Yup. He had to be out and about at the very moment my parents decided to send Mabel and I out to thicken our skin and test our nerves.

“Ew. I told you to stop that. It’s creepy.“ Mabel pulled away, going on the defensive with her bat.

“What do you want, Gideon?” Hopefully he will just get to the point.

“Just to play with my best friends of course.” The sarcasm could be tasted in the air it was so thick.

“Oh wow! I didn’t realize that you had _friends_. I should have known that there's gatta be someone for everyone. We won't keep you from meeting them. ” I grabbed Mabel’s hand and headed to go deeper into the forest.

That was were everything went wrong. Gideon yelled while turning a slight shade of pink from either rage or embarrassment. Hard to tell with how messed up he is. “Pines…. _Venite post bestiam. Ascende_!”

I looked back to see a circle on a piece of paper in his hand. Gideon must have pulled from his pocket. He laughed terribly, and by terribly, it was just that. It sounded as though he was tone deaf, but with his laughter and not singing. It was honestly ruining the moment I think he was going for.

Before the demon could completely materialize, it was a home run. With her bat, she sent the half summoned creature into the woods at near record speeds. “Aaaand, Iiiit’s Outa here!”

Gideon took a moment to realize that his monster was gone. His master plan was foiled in less than a two paragraph summary.  He shook a little as he huffed, “You, you might have won this round hiding behind your angel of a sister...but this isn’t over...” He hurried of. Probably to cry.

I couldn’t hold back the laughter at that thought. Mabel looked at me with a rather worried look on her face.

“You gatta stop picking fights with him bro...”

My laughing stopped and turned to a pout.

“He started it.” It was mature of me, I know, but still. It was Gideon that started it. I just decided that we should finish it. Wasn’t expecting the demon. That was new for him.

“Doesn’t mean you need to egg him on.” She held back a grin for a moment before she punched my arm lightly. “That was pretty good though. You see how far I sent that thing?”

I grinned back. “Heck yeah I did!”

__

So, you must be wondering what this little exchange with Northwest had to do with Mabel’s broken arm. Well, we hadn’t broken the circle that summoned the monster. Mistake #1.

That night, little after dinner, Mabel and I were doing our own thing in our room. She was working on her latest art thing (I wasn’t going to ask this time. Last time, I ended up having to help her compose five or six musical numbers) I was immersed in some books.

Gideon’s voice rang out from the yard.

“Man, It would be worth summoning a demon to just get him to leave us alone!” I slammed by book shut and glared at the window.

“Hey now. You know that kinda thing shouldn’t be done lightly...” Mabel threw a pen at me. I tried dodging it. I did successfully avoid the pen, but it caused me to collide with the bedpost. Damn it.

Mabel got up and opened the window, climbing to the roof that stretched from our window. Mistake #2.

I followed as well to see Gideon summoning that demon again. This time, it was already fully summoned. A Kobold? What bad taste. What was it going to do? Clean our room?...Though our room could use a cleaning...

While I had my musing of Gideon actually providing us with a kind gesture, Mabel started to fight with the creature. I guess she was defending my honor or something. I kinda spaced so I don’t know what actually was said.

Then we have Mistake #3!

“Take this!” With a swing of her bat, the creature was once again gone, but in the swing, she had lost her footing.

“Mabel!” I hurried to help catch her, reaching my arm to her’s as she went falling from the second story roof.

I reached and I grabbed. I was just close enough to be able to save her from the fall. My hand closed on air.  Damn my depth perception.

 _SN_ AP!

__

And that was why my straw got stolen by my twin. Ultimately, Gideon was the one that caused her to break her arm, but I couldn’t help but feel as though it was my hand that pushed her...like through the chain of events kinda thing. Cause I pick fights. And junk like that.

So I was gunna fix it. “Mabes, you need anything before I head to the library?”

“Nope. I’m good. Oh Oh!” She hopped a little and leaned over the sofa arm. “Could you grab me some things on your way home?”

“Depends on the thing...”

“Well, maybe the normal candy bars and a soda? Oh! don’t stay out too long. Tonight is Pizza Night! Everyone’s coming over and we’re gunna watch Sooooo many movies”

Hopefully not all romancy garbage. “Yeah yeah, I’ll be home on time with as much soda as I can carry.”

“You’re the best.” Mabel gave a thumbs up before she was stolen back as commercials had ended.

I waved and left and headed to the forest with my backpack completely stuffed.

Man, she had to make a request. Now I have to make sure that I don’t mess up. Darn her sometimes. I bet she figured it out I wasn’t heading to the library.

“Aaaugh! How is she always able to do that! Acting like she actually thinks I’m heading to the library. She never requests stuff when I head there!” I shouted to no one, surrounded by the company of the trees.  

Whelp. Might as well do the deed, make my payment-which I hope won't be too bad- and head home.

With some rather skillful gestures, the perfect Summoning circle was drawn. I’d covered all the loopholes and ways out the circle could have-least to my knowledge, which not to toot my own horn or anything, but I’m pretty damn good at this for some reason.

Here goes.

“ _Astrum splendidum, te invoco. Te invoco ut facias voluntatem meam. Dico nomen tuum: Alcor!_ ”

The circle I had created started to show signs of activity. It worked?!

I couldn’t help but let the grin grow on my face. I should be freaking out, but at the sight of all the power that spilled from the mere fact that I had spoken the right incantation. I couldn’t contain the glee.

Laughter escaped my throat as the demon began to take form.

The creature was terrifying and glorious. It’s form was black, covered in golden cracks, Blue flames burning all around.  

I couldn't help but feel almost refreshed at the sight. It was strange.

Then the demon spoke, in a voice that echoed with the sound of the ages. As angry as the tone he spoke in, I didn’t feel fear at all. It was a strange kind of pleasure.

 

“ **...** **Bill.** ”

**Notes for the Chapter:**

> Ok...so many head canons later, this kinda happened. I was going to post out the ones that I really enjoyed, but I kinda lost track of them by the time that I'd finished writing this... though one post about Mabel's twin being Bill reincarnated, And how Dipper would deal...I just couldn't resist. [also, I wrote it in first person to kinda keep Bill on the down low. Did it work?]
> 
> This is my first time ever writing and posting something like this online so critic's are welcome. Next chapters probably going to be from Dipper's perspective, but I'm not 100% sure...


	2. Deal

**Notes for the Chapter:**

> I changed the POV to 3rd person for now. Might only do first person when in Bill's head.

_Bill..._

_How long it’d been since last our paths crossed. To think, you, the once powerful creature would be in such a small and frail looking body. All those cynical desires are still there. It’s almost reassuring that inside, there hasn’t been much change. How easy it will be to corrupt and manipulate those desires._

The reaction of seeing Bill faded from shock to a strange twisted pleasure.

At seeing the small body, such a frail meatbag, housing such a twisted demon soul, it was impossible to hold back the laughter. It wasn’t a full hearty laugh like the boy had been doing. More controlled and a little more sinister.

At hearing Alcor’s laughter, Bill took a deep breath to settle his own. His sacrifice wasn’t a large one, so he didn’t have long to make his request, though the look of ecstasy still on his face. “The books weren’t kidding when they powerful! This is wonderful!”

“Indeed.” This boy, his existence. meeting after all this time. Alcor never _sought_ revenge, nor was it ever something he really thought of. But he was also a bit of an opportunist, and well, the opportunity had arrived. This was going to be fun…

 

“Now tell me, what is it that you desire?” Alcor’s power flickered slightly, the blue flames dancing around the circle. The eagerness to corrupt Bills wish, just as Bill had done to him so many years back, was feeding the flames. Well, not really corrupt, but more take advantage of a loophole to get the better end of the deal.

“I want to heal my twin’s arm. She...It’s important to her to be able to create, and her arm is important for that...”

The words that exited the boys mouth betrayed all that Alcor could see in Bill requesting. Every ounce of this boy’s soul screamed for the chaos, even as Bill stated his reason for summoning Alcor, the request seemed to push the kids will. Whether or not bill himself was aware of it. What was suppressing it?

“Arms heal on their own. You sure you want to dish out the payment to heal it faster?” The demon looked to him a glint in his eye.

“They do....Her’s is broken bad...It will heal, yeah, but chances of it healing right...Her arm will always have problems even if she never tells anyone about it. It’s not just me guessing or being a pessimist. I can’t explain how I know, but I _know_ that it will cause her pain for the rest of her life...I can see it.” Bill looked away with a complicated look on his face, his hand covering the eye covered in a patch -a mix of frustration at his wish and something else maybe? Maybe Bill was aware of something else he wanted to wish for something else?

He was aware of the chaos he wished for. He was suppressing it somehow. Alcor could only figure as much while watching the boy’s soul flicker.

“I”m willing to pay the price, whatever it is...”

How? A demons root nature -Alcor knew first hand- was not something that could easily be resisted. His human past was what kept it under wraps but even then there were slips almost more often than not after Mabel’s passing.

This body. That was it. The human body, the humanity that was forced on Bill.

The white teethy grin grew brightly across Alcor’s shadowed out face.

 

“The payment will be control of your body.” He floated closer to the boy, who at hearing that, looked terrified. _So delicious, that fear._

“To be more precise, it will only be till I’m bored with it. Then if its still _intact_ when I’m done with it. It’ll be yours again.” That seemed to scare Bill even more, Alcor could see it. Guess the thought of coming back to a body that was in terrible pain would be far more scary than never feeling again. And was Alcor going to have _fun_ with that body.

 

Bill took a breath before a grin betrayed his fear, or maybe he enjoyed the fear? “Fine. Mabel has to be healed before you can have my body. I have to be able to see her arm out of the cast and working right.”

Alcor extended his hand to Bill, Blue flames engulfing it. “Sure thing kid.”

“And you can only do it once. Once you leave my body alone, that’s it. Playtime will be over.” Bill took the extended hand and the flames grew to cover his own arm as well.

“Quite a few demands for such a small thing...It’s a deal.”  As the flames binded the contract, Alcor revealed his body from the shadows, taking an age that matched Bill’s. 12. What a memorable age.

__

“Bill Bill!!” Mabel came rushing out of the house once she heard the front gate open. “Biiiiiilllllll Loook!!” She was waving her arm that should have been in a caste arounds wildly.  “It was so weird! My arm caught on fire then it was all FUME and it burned the caste off. And once the fire went out, my arm was healed!”

“That’s awesome!” Bill smiled, a little nervous. There there was a weird pulling feeling, like he was getting ripped from his own body. Everything went white.

“Now tonight’s movie night will be soooo much more exciting! We can do so much more. Good thing you loaded up on soda and snacks!” Mabel looked to Bill’s empty hands. Well, they weren’t empty, as he held his backpack.  They weren’t holding the bags of snacks she was expecting.

“You forgot to get the snacks…” She looked  a little disappointed. “Don’t tell me that you got so absorbed in reading again...”

“Sorry Mabel. I actually forgot my money here. I needed to come back for it.” Bill’s voice had an unusual tone to it. “How about we go together once I grab my wallet? Maybe get some ice cream to celebrate your arm healing?”  

Mabel paused for a moment, looking at her brother with a slightly confused look. Something was off, but then again, he did that sometimes…”Sure. Mind grabbing my bat with the stickers on it too while you are up there?”

“Yeah, Sure thing. Be back in a sec.” Bill ran to the room they shared, about halfway up the stairs, he started to laugh.

“ _Ahahahaha!_ ” Once in the room, the demon was having a hard time containing himself.

What a turn of events, Bill was Mabel’s little brother now. Alcor couldn’t contain his joy. It was like this was a reset button. And Bill had _given_ him this body. _How wonderful! How wonderful_!

Bill watched helplessly as his body twitched with excitement from the mindscape. Only able to hover there.

 

**Notes for the Chapter:**

> I hope you enjoyed this as much as I enjoyed writing it~ I have a few more chapters planned out yet also. I freaking love what I've got in store~ (also, any opinions as to my writing? Still kinda new at this)
> 
> Oh~ also I drew a picture for it too: http://ventiset.tumblr.com/post/99956206041/bit-of-a-spoiler-picture-for-a-fic-im-writing-for


	3. Candy

**Notes for the Chapter:**

> Sorry about being MIA for a bit! Here is Chapter 3~ Hope it was worth the wait!

“Everything ok? You were taking a while.” Mabel walked into our room to find My body still in hysterical laughter

“Yeah, Everything is _wonderful~_! I just. I just thought of something terribly funny from an earlier time.” Alcor [in my body, boy is that weird] held up my wallet as he took a few breaths to calm down. “Got my money, shall  we head out?”

Mabel looked at Alcor a little bit strangely before nodding. I wonder if she could tell it wasn’t /me/ though I’m not too surprised that the laughter wasn’t a give away. Sometimes, I would have a habit of acting like that...though it would only be after weird dreams, or if I stayed up too long and started to daydream. I’ve done it in class once, that wasn’t fun. I’m not 100% sure how often it happens. I tend to forget what triggers it, or even just when it happens. Most people tell me about it after the fact.

Little creepy that I share this kinda parallel with a demon.

“Let’s hurry! We only have so much time before we are late for our own party!” Mabel grabbed her favorite bat with one hand, then with the other grabbed Alcor. With a burst of energy, she dragged him outa the house. I hovered after them.

“Might as well go along to see what kinda hell I’ll have to fix once I get my body back.”

Alcor was holding a conversation with Mabel pretty well. How gross. I was that easy to imitate? Or was it some strange demonie power that let him access my brain like a flash drive for mannerisms or memories and junk. Then again, it wasn’t all like me too. But similar. Maybe we were of a similar nature. Hehe, Kinda chilling really. A demon like me, or was it that I was like a demon?

Not paying attention, I went through a tree.

“Pfft, Ah-ha.” I held back my laughter. Couldn’t risk Mabel hearing. Alcor glanced over to me with a grin and nodded at me.

Did that mean it was ok? I mean some ghosts could be heard. Then again, they used a vessel of some sort.

I went through a pole this time as we got closer to town.

“Ha ha...Ahahahaha! This is so neat!” No need to stay silent as I started to go through everything! This was fun! I might as well enjoy it till I got my body back! “Nothing can stand in my way! I’m the mighty powerful Bill~!”

I froze up for a moment when I caught a twisted grin from Alcor’s direction.

I followed a little uneasily for the rest of the way to the store. Only Mabel’s cheery game plan put the feeling to rest.

“I’m getting the soda. You’re on snack duty bro! ” With a burst of energy she bolted to the next aisle over. “You know what to get!”

I watched as Alcor stared at the snacks, clearly confused.

“She likes those.” I pointed to the skittles, “And those, and those. Then I like these.” I continued to point to items. “but you can get whatever you like, though avoid the red cinnamon candies.”

“Why...”

“They don’t agree with my stomach and if you don’t wanna spend you time in my body praying to the toile-”

“No. Not what I meant!” Alcor cut me off. “Why are you telling me this?”

“Well, Mabel told _me_ to get the snacks. Seeing as I’m here, and just can’t touch them, pointing them out is least I can do.” I crossed my arms as I hovered there. “Snacks are the vital point of movie night.”

Alcor looked at me. obviously confused...or maybe mad? “You’re far too accepting of this...”

I shrugged. “It was for my sister. I’ve done worse to make sure she is safe.”

“Clever boy...” Alcor let out a confusing laughter. Maybe he was trying to figure out what was worse than having a demon have control of your body? Or maybe it was that he knew what I’ve done, that whole omnipresence thing some demons were supposed to have.

__

Mabel could hear her brother laughing from the snack aisle. Something about him was off. Same time, he would be like that sometimes after hanging out in the library all day. She held onto the sodas with the hand that just this morning couldn’t hold anything.

“Wait a second, earlier Bill needed to get his wallet from upstairs...but without his wallet, he couldn’t get anything from the library...Or even take the bus to get there…” She mumbled to herself as she looked in Bill’s direction.

That little brother of hers. He probably did something again. “Darnit Bill...” She knew if she asked him, Bill would deny everything, maybe even come up with an elaborate plan blaming Gideon. Like saying that guy felt soo bad about hurting his sweet angel, that he summoned one of his pets to heal Mabel up.

Nope, when asking Bill, there was no such thing as a straight answer. She would have to trick it out of him. Or corner him.

“You get everything?” She hurried to her brother’s side.

“You bet! I figured I’d grab a bit extra also” Alcor held out the spoils. I’d been a while since he’d had the candy he could pick.

“We are gunna get soooo hyper.” Mabel grinned. “To the check out!!” She pointed her finger out to lead the charge.

Alcor laughed and followed suit.

Once they finished up and headed home, Mabel looked to Alcor once they were away from people. With a deep breath, Mabel looked to Alcor before saying “So what did it cost?”

“You were right there, it was like $15-something.” Alcor was cheerfully swinging the bag of candies back and forth.

“I’m not talking about the candy.” She stopped at looked him dead in the eye and held out her healed arm.

“Oh...” He looked away. Pretty docile for a demon.

“Bill. What did you do…?” Mabel looked worried now. It could be heard in her voice.

Bill found himself looking away very much like Alcor.

“ _Bill Henry Pines_. I know you. What did you do...”

Alcor, no, Dipper would be better to call him by, murmured out. “We-I made a deal...It’s a pretty harmless one...” Without looking, both Bill and Dipper could feel Mabel’s overall worry for her brother. For Dipper it hurt more because it wasn’t love for him.

A jealously raged in the demon. This body was his from the deal. If he made up something, then, there would be no need for her to even attempt to save her brother. He could keep it as Bill watched from afar. It would be just like before.

There was a spark of yellow in Dipper’s-in Bill's eyes as he looked back to Mabel. “The deal was that I had to give up my fondest memory. A small price for your health.”

His grin gave Mabel chills. One missing memory couldn’t alter someone this much. This wasn’t Bill...What was before her, wasn’t her brother.

  



	4. Update Soon.

**Summary for the Chapter:**

> ~~Sorry for no updates in the longest time, I have it all written, not typed. Life did a nice round house kick to the face and I'm recovering (been soo beyond busy) hopefully by the end of the month I'll have the final chapter~~~

Small  doodle for now. 

(2017 edit: I ended up losing the original draft for last chapter so gunna be writing it again. I feel bad for the cliff hanger)

I also have all the art I've done for this in a stash folder on da: http://sta.sh/27ljzldgviw 


End file.
